BS-11 PLL clock source / calibration

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Dieter Spaar spaar at mirider.augusta.de
Thu Apr 30 08:23:00 UTC 2009


Hello Christian,

On Thu, 30 Apr 2009 03:13:33 +0200, "hotshot" <hotshot at koeln.ccc.de> wrote:
> 
> Unfortunately I see the same behavior  (even with restarting the
> BS-11) as in E1-locked ('hfcmulti' and 'hfcmulti port=0x200) - a
> network scan shows either your BS-11 or the other networks and only
> sometimes you see all networks

In the latest OpenBSC version there is support to show the "Set Value"
and the "Work Value" of the PLL setting. The "Set Value" is the
configuration value from the factory. The "Work Value" is not 100%
clear yet but most certainly it is the value the PLL is actually
using. In "Locked" mode the PLL follows the E1 clock and the
"Work Value" can change quite a lot. Switching to "Standalone"
mode seems to freeze the current "Work Value". The question now
is if the PLL still used this "Work Value" in "Standalone" mode.
If yes and the "Work Value" is off by a large amount the clock is
not accurate (although its most certainly stable) and you still
won't the test network and the other networks at once.

If the "Work Value" of your BS-11 is off by a large amount from
the "Set Value" you can try to switch to "Locked" mode and watch
if the "Work Value" follows the E1 clock. If its close to the
"Set Value", switch back to "Standalone" mode.

I have not tested this and I don't know a better way yet (I don't
think the "Work Value" can be set from the outside) but you can
give it a try.

Best regards,
  Dieter
-- 
Dieter Spaar, Germany                           spaar at mirider.augusta.de




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